Apparatus for the deformation of metal sheets



P. NEMITZ v 35403539 APPARATUSFOR THE DEFORMA-TION OF METAL S PIEE TS Filed Oct. 19, 1966 B 6 "llll flll lll UN VIII'IIIIIIIl/IIIIIIIIAYIIL I/VVENTOR':

PAUL NEH/T2 ATTORA/US.

United States Patent 3,403,539 APPARATUS FOR THE DEFORMATION OF METAL SHEETS Paul Nemitz, Kiel-Pries, Germany, assignor to Atlas- MaK Maschineubau G.m.b.H., Kiel-Friedrichsort, Germany, a firm Filed Oct. 19, 1966, Ser. No. 587,754 3 Claims. (Cl. 7256) This invention relates to an apparatus for the deformation of metal sheets under shock effect in water, wherein a sheet metal disk is placed on a mold and held in place by a holding down appliance.

Apparatuses of this type are already known. In one known embodiment the holding down appliance is secured at the outer edge by means of marginal screws to hold down the sheet metal disk. In the case of large sheet metal disks, however, the marginal screws do not sufliciently force down the annular holding down appliance against the sheet metal disk.

Even when hemispherical indentations with diameters of 1 m. are to be shaped, folds are formed at the outlet of the drawing die due to the lifting of the holding down appliance in the end phase of the deformation process. Furthermore, these folds have the effect that additional stresses are exerted on the marginal screws which have been tightened under maximum tensile stress, whereby unscrewing of the screws is rendered particularly diflicult.

Attempts have been made to overcome this deficiency by using hydraulically operable clips in the form of screw clamps. However, this proposal is not realizable in practice because the number of the hydraulically operated clamping units to be disposed on the circumference of the edge of the mold becomes so large and the weight of the clamping units so high that the operation becomes very expensive. Moreover, the connection hoses for the clamps would be considerably hindering when operating the latter.

It is the object of the present invention to eliminate these disadvantages hitherto existing in the deformation of large-sized sheet metal disks. This object is achieved according to the invention in that the mold is placed on a vertically adjustable base plate inside a container which is open at the top and that the annular holding down appliance carries on its inner edge a plurality of pivotable clamping pawls which are distributed radially over the circumference of the holding down appliance and engageable with their free ends under an inwardly projecting flange on the upper edge portion of the open top container.

A container which is open at the top is necessary in all cases where no mold of cast steel is used but the mold consists of concrete, ice or a sheet metal body reinforced by ribs. If a mold consisting of concrete or ice or a sheet metal body is used, such a container is indispensable since the shock waves acting upon the sheet metal disk are reflected as suction waves during their passage through the mold when upon leaving the mold the surrounding body is of a lower density than the mold as, for example, in the case of air or water.

The wall of the container consisting of steel and surrounding the mold reflects the approaching shock waves as pressure waves. After placing the holding down appliance onto the sheet metal disk the free ends of the clamping pawls can be brought to engage under the flange of the container. In order to achieve a sufficient contact pressure, pressure medium operated props are provided between the stationary bottom of the container and the vertically adjustable base plate, which props ensure uniform lifting and provide the adjustable contact pressure needed to obtain proper clamping of the sheet metal disk by the holding down appliance.

With the aid of the invention it is possible to deform large-sized sheet metal bodies in a quick and simple manner. The uniform distribution of force over the adjustable base plate ensures a uniform application of pressure to the sheet metal disk.

One or more pressure medium operated props may be provided under the adjustable base plate, the number depending on the required application of pressure as well as the size, thickness and density of the sheet metal disk to be deformed.

Several embodiments of the invention will now be described by way of example and with reference to the accompanying drawing, in which:

FIG. 1 is a cross section through a deforming apparatus according to the invention with the holding down appliance not yet fixed;

FIG. 2 is a cross section through another embodiment of the deforming apparatus with the holding down appliance fixed, and

FIG. 3 is a cross section through still another embodiment with the holding down appliance fixed.

With reference now to the drawing, a mold 1 consists either of concrete 3 or ice (FIG. 1) or a sheet metal body 6 reinforced by ribs 5 (FIG. 2) or cast steel 2 (FIG. 3). On the mold 1 a sheet metal disk 7 is placed which is to be deformed by forcing it into the mold 1 under shock effect. The mold 1 is provided with a holding down appliance in the form of a ring 8.

The mold 1 rests on a vertically adjustable base plate 9 inside a container 10 which is open at the top. Between the vertically adjustable base plate 9 and a stationary bottom 11 of the container 10 pressure medium operated props 12 are arranged. A flange 14 is provided on the inner side of the upper edge 13 of the open top container 10.

Carried on the ring 8 for holding down the sheet metal disk 7 are clamping pawls 15 which are pivotally mounted by means of pins 4 on the inner edge of the ring 8 and distributed radially over the circumference of the ring. With their free ends of the clamping pawls 15 are engageable under the flange 14 as illustrated in FIGS. 2 and 3. The pressure medium operated props 12 between the vertically adjustable base plate 9 and the stationary bottom 11 of the container 10 ensure that the sheet metal disk 7 is sufliciently pressed against the mold 1.

The invention may be embodied in other specific forms without departing from the spirit or essential characteristics thereof. The present embodiments are therefore to be considered in all respects as illustrative and not restrictive, the scope of the invention being indicated by the appended claims rather than by the foregoing description and all changes which come within the meaning and range of equivalency of the claims are therefore intended to be embraced therein.

I claim:

1. An apparatus for the deformation of metal sheets under shock effect in water, comprising (a) a mold,

(b) a vertically adjustable base plate on which said mold rests,

(c) an open top container having an inwardly projecting flange on the upper edge portion thereof and accommodating said vertically adjustable base plate,

(d) an annular holding down appliance for holding a sheet metal disk in place on said mold, and

(e) a plurality of pivotable clamping pawls carried on the inner edge of said annular holding down appliance so as to be distributed radially over the circumference thereof and engageable with their free end under said inwardly projecting flange on the upper edge portion of said container.

2. An apparatus as claimed in claim 1, wherein at least one pressure medium operated prop is arranged between the vertically adjustable base plate and the: bottom of the container.

3. An apparatus as claimed in claim 2, wherein the clamping pawls are linked to the holding down appliance so as to be pivotable out of their working positions.

References Cited UNITED STATES PATENTS RICHARD J. HERBST, Primary Examiner. 

1. AN APPARATUS FOR THE DEFORMATION OF METAL SHEETS UNDER SHOCK EFFECT IN WATER, COMPRISING (A) A MOLD, (B) A VERTICALLY ADJUSTABLE BASE PLATE ON WHICH SAID MOLD RESTS, (C) AN OPEN TOP CONTAINER HAVING AN INWARDLY PROJECTING FLANGE ON THE UPPER EDGE PORTION THEREOF AND ACCOMMODATING SAID VERTICALLY ADJUSTABLE BASE PLATE, (D) AN ANNULAR HOLDING DOWN APPLIANCE FOR HOLDING A SHEET METAL DISK IN PLACE ON SAID MOLD, AND (E) A PLURALITY OF PIVOTABLE CLAMPING PAWLS CARRIED ON THE INNER EDGE OF SAID ANNULAR HOLDING DOWN APPLIANCE SO AS TO DISTRIBUTED RADIALLY OVER THE 